1. Field of the Invention
The present invention relates to a decurl unit and a printing device.
2. Description of the Prior Art
One proposed decurl unit attached to a printing device, which uses recording roll paper as a printing medium, is capable of adequately eliminating curl with a decrease in remaining amount of the roll paper. For example, in a decurl unit 50 disclosed in Japanese Patent Laid-Open Gazette No. 9-25036 (see FIG. 7), a support member 522a is attached to a pivot shaft 522b in a rotatable manner to support a decurl roller 522. A torque clutch (not shown) works to transmit a practically constant torque to the pivot shaft 522b. As the remaining amount of roll paper 521 decreases (see the one-dot chain line in FIG. 7), the torque clutch rotates the pivot shaft 522b and moves the decurl roller 522 in a direction to be pressed against the roll paper 521 (that is, in a direction of an arrow F in FIG. 7). This action eliminates curl of the roll paper 521 passing through the decurl roller 522.
In the prior art decurl unit 50, however, the decurl roller 522 rotates about the pivot shaft 522b, as the remaining amount of the roll paper 521 decreases. An extra space is thus required between the roll paper 521 and conveyance rollers 525 for rotation of the decurl roller 522. This undesirably interferes with size reduction of the whole decurl unit.